Sneak Leveling

Quick Sneak Leveling

To accomplish this, you will need a dagger of any kind, but preferably one with a higher damage rating/health drain enchantment if you want to kill two birds with one stone.

In High Hrothgar, after you have learned the "Ro" shout for Unrelenting Force, find Einarth in the hallway towards the back left from the main entrance to the building. He will be kneeling down praying. Equip the dagger and sneak up behind him. Make sure not to move and attack him repeatedly. You will begin to level up Sneak very rapidly. Einarth will eventually stand up but as long as you stay behind him and do not move while attacking, he should not turn around. If you mess up, he will immediately use the Ice Form shout and you will have to deal with a handful of very pissed off greybeards. I would recommend saving every few levels or so. Depending on how high your sneak level is, you should level up every second to fifth dagger attack. You should be at level 100 in under an hour, depending what your level was previously.

Einarth has a lot of health/resistance to damage, and as part of a Main Quest, he cannot die. If you use a powerful dagger that drains health, you can use Healing Hands in your other hand and level up Restoration as well, though it is not nearly as fast the Sneak leveling.. An Iron dagger, or something of the like, would not damage him enough for you to use Healing Hands for very long, but would still level Sneak.